A small passenger jet barreled into a hangar at a California airport Thursday night just ten yards from the terrified workers inside the building.

Just after 6 p.m., the small Bombardier Challenger jet crashed into a hangar with at least four inside at Chino Airport in southern California, KTLA reported.

Before the 60-foot long plane ended up in the hangar, its engines were running at full speed as it underwent an engine test. The jet somehow lurched over the rubber chalks used to hold planes in place on the tarmac.

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Accident: A small passenger jet crashed into a Chino Airport hanger that had at least four workers inside

On Alert: After the crash, firefighters shut off electricity because they were afraid of leaking fuel

Emergency: Fire crews were on scene to hose down the wreckage

Danger: Three mechanics were on board the small jet when it crashed

'The plane was chalked on the ramp area while undergoing an engine run-up test,' FAA spokesman Ian Gregor said in a statement.

'At some point, the plane jumped the chalks and ran into the hangar,' he added.

After the crash, fire crews hosed down the wreckage, KSTP-TV reported.

'I walked out and looked down the hallway
and just saw a huge fuselage sticking through the middle of the hallway
and knew immediately what happened,' he said. 'There was three others
and we all just started running out of the building.'

'Like a bomb going off': Witnesses said the crash sounded like an earthquake or bombs

Crash: National Transportation Safety Board investigators will arrive at the site of the crash Friday

Overhead: The small jet crashed while it was undergoing an engine test

Rand was conflicted when the crash occurred.

'I was thinking, you know "Is the plane going to blow up...Is there anything that's going to cause it to blow? Should I get far away from it?"' he said. 'But I also knew that there were other people in the plane, so I was conflicted you know whether or not to try to get them out or get far away or what to do...it was kind of hectic.'

Another witness, Robin Dill also said the crash sounded 'like a bomb going off'.

Dill, a retired commercial airlines captain with 32 years experience, told KTLA he thought the mechanics should have immediately put the plane in idle.

'I can say--and I think most pilots would agree--that if the airplane was operating at idle engine speed, the aircraft would have stopped and wouldn't have continued like it did,' Dill said.

Investigators with the National Transportation Safety Board will arrive at the airport Friday morning to try to figure out what happened.